This invention relates to an electrical circuit for an air conditioner and more particularly to a protection circuit for an air conditioner having an electric heater.
U.S. Pat. No. 4,898,230 has disclosed a control system for an air conditioner which may be characterized as having a bimetallic temperature switch or the like connected in series with an electric heater such that the switch opens and the electrical power supply to the heater is cut off when the temperature of the heater exceeds a set level. With such a control system, however, the maximum current which can pass through the switch must not be less than that through the heater because they are connected in series, and this tends to slow down the opening and closing of the switch. In order to compensate for this slow down, the temperature setting must be made somewhat lower but, if a lower temperature is set, the switch may be inadvertently activated when, for example, the filter has become choked and the air flow by the air circulating system reduced.